Internal Damage is a special sort of Armor-Negating Damage that hits a poor fellow from the inside out. It is extra tough to prevent; Elemental Resistances that line up can reduce the damage, but that's about it. Mossbody and Mistform don't reduce the damage, for example.

The following deal "internal" damage:

• Being grilled from the inside by Incinerate
• Extreme pneumonia caused by Sailors' Death
• Getting your blood boiled by Blood Boil
• Having your heart frozen by Frozen Heart
• Having some of your blood replaced with Poison by Blood Poisoning or Venomous Death
• Getting overloaded by Stream of Life and exploding ("instakill")
• Getting transmuted into dust by Disintegrate ("instakill")

Note that the things Internal Damage bypasses are generally not strong enough to prevent an "instakill" from instantly killing, even with Luck.

Set damage that doesn't get a DRN roll to increase or decrease it, also known as "true" damage, is also internal.